Cyclic gaseous compression/extraction for heightened oil sands extraction

ABSTRACT

A method for extracting hydrocarbons from sands can include: providing sands containing a hydrocarbon; mixing the hydrocarbon sands with water; heating the water before, during, or after being mixed with the hydrocarbon sands; increasing the pressure within a closed vessel containing the heated hydrocarbon and water mixture in the presence of gas or by injecting with gas; releasing the pressure of the heated hydrocarbon and water mixture in the vessel so as to create microbubbles from the dissolved gas in the water mixture; and collecting the hydrocarbon from the water. Optionally, the process is substantially devoid of adding caustic agents to the hydrocarbon and water mixture.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims benefit of U.S. Provisional PatentApplication Ser. No. 60/985,078, filed Nov. 2, 2007, and U.S.Provisional Patent Application Ser. No. 61/049,056, filed Apr. 30, 2008,which provisional applications are incorporated herein in their entiretyby specific reference.

BACKGROUND

Population centers in the U.S. and around the world are facingincreasing challenges to provide sufficient energy, and will continue todemand new technologies for preparing usable energy resources for publicconsumption. Accordingly, attention is being turned from conventionaloil deposits to oil sand deposits. However, the technologies availablefor obtaining bitumen from conventional oil deposits are not suitablefor obtaining bitumen from oil sands.

Oil sand deposits in northern Canada contain about 142 billion cubicmeters (or 890 billion barrels) of bitumen, thus constituting thelargest oil sands deposit in the world. In the Athabasca region ofAlberta, the oil sands deposit is typically composed of (by weight)about 12% bitumen, 82% to 85% mineral matter (solids), and 3% to 6%water. Of the solids fraction, the solids smaller than 45 microns insize (e.g., silt and clay) are referred to as fines. The clay fractionof the fines can be a significant factor in processes for bothextraction of bitumen and disposal of oil sand tailings (e.g., residuefrom primary oil sand processing).

The bitumen of the Athabasca deposits has been commercially extracted byvarious oil sand-water slurry-based extraction processes and thermalin-situ processes. The liberated bitumen can be upgraded to syntheticcrude oil at a production capacity of over one million barrels per day.In the major bitumen recovery operations in the Athabasca region,bitumen is produced from surface-mineable oil sands usingwater-slurry-based extraction processes, in which the oil sands “ore”(e.g., the raw oil sand material, as excavated from the oil sanddeposits) is mixed with hot water to form an ore-water slurry. Asphalticacids present in bitumen, which contain partly aromatic oxygenfunctional groups such as phenolic, carboxylic and sulphonic types,become water-soluble, especially when the pH of the ore-water slurry isslightly over 7, and act as surfactants reducing surface and interfacialtensions. Reduction of the surface and interfacial tensions of theore-water slurry system results in the disintegration of the orestructure and liberation of bitumen from the ore. Accordingly, thewater-liberated or water-extracted fraction of bitumen asphaltenes playsan important role in the recovery of bitumen from the surface-mineableoil sands.

However, oil sands in different regions are chemically different andextraction processes that are successful for the oils sands of oneregion may not be sufficient for a different region. The selection ofrecovery and treatment processes of different oil sand deposits areinfluenced by the properties and composition of the oil sands and thebitumen. Since Canadian oil sands contains more moisture than Utah oilsands, optimal extraction methods for Utah oil sands are likely to bedifferent from those in Canada. Thus, there remains a need fordeveloping different oil sands extraction methods that can be applied tothe various different oil sands or to particular oil sands, such as theUtah oil sands.

SUMMARY

In one embodiment, a method for extracting hydrocarbons from sands caninclude: providing sands containing a hydrocarbon; mixing thehydrocarbon sands with water; heating the water before, during, or afterbeing mixed with the hydrocarbon sands; increasing the pressure within aclosed vessel containing the heated hydrocarbon and water mixture in thepresence of gas or by injecting with gas; releasing the pressure of theheated hydrocarbon and water mixture in the vessel so as to createmicrobubbles from the dissolved gas in the water mixture; and collectingthe hydrocarbon from the water. Optionally, the process is substantiallydevoid of adding caustic agents to the hydrocarbon and water mixture.

The hydrocarbon can be any hydrocarbon, such as bitumen, tar, andmolecules that can be processed into fuel. The gas is selected from thegroup consisting of air, N₂ (nitrogen), O₂ (oxygen), CO₂ (carbondioxide), Ar (argon), BF₃ (boron trifluoride), CH₄ (methane), C₂H₂(acetylene), C₂H₄ (ethylene), H₂S (hydrogen sulphide), C₂H₆ (ethane),C₃H₆ (propylene), C₃H₈ (propane), 1-butene, 1,3-butadiene, vinylchloride, 1,1,1,2-tetrafluoroethane, isobutane, n-butane, isobutene, orany mixtures thereof.

The sands and water can be conditioned in batch tumblers or conditioningdrums or are mixed during transport through a pipeline.

The process can be performed with at least one of the following:increasing the pressure to a range of about 10 to about 210 psi followedby reducing the pressure by at least 10 psi; maintaining the temperaturebetween about 20 degrees C. to about 120 degrees C.; cycling thepressure for about 2 to about 30 pressure cycles; solid water volumeratio is from 0.1:1 to 2:1; increasing the pressure at a rate ofcompression that is about 5 to about 300 seconds to reach maximumpressure; or decreasing the pressure at a rate of decompression that isabout 0.01 to about 300 seconds to vent to reach ambient pressure or anyother lowered pressure.

The process can further include introducing the hydrocarbon and waterinto primary separation vessel (PSV). Also, the process can furtherinclude settling the mixture into stratified layers in the PSV: impurebitumen froth on the top; a combination of bitumen, sand, clay and waterin the middle (middlings); and sand precipitated to the bottom. Theprocess can further include pumping the precipitated sand into asettling basin with water to form tailings. The process can furtherinclude separating the hydrocarbon from the tailings. The process canfurther include separating and cleaning the middlings by gas injectionand steam de-aeration. The process can further include recovering thehydrocarbon from the middlings. The process can further includerecovering the hydrocarbon from the froth.

In one embodiment, a method for extracting hydrocarbons from a particlecan include: providing a particle containing a hydrocarbon; mixing thehydrocarbon-containing particle sands with water; heating the waterbefore, during, or after being mixed with the hydrocarbon-containingparticle; increasing the pressure of the heated mixture within a closedvessel; releasing the pressure in the vessel so as to createmicrobubbles in the mixture that liberate the hydrocarbon from theparticle; and collecting the hydrocarbon from the water and particle.The pressure can be increased by any of the following; by decreasing thevolume of the vessel; by increasing the number of molecules in thevessel; or by increasing the temperature in the vessel; by injecting agas into the vessel. The gas can be selected from the group consistingof air, N₂, O₂, CO₂, Ar, BF₃, CH₄, C₂H₂, C₂H₄, H₂S, C₂H₆, C₃H₆, C₃H₈,1-butene, 1,3-butadiene, vinyl chloride, 1,1,1,2-tetrafluoroethane,isobutane, n-butane, isobutene, or any mixtures thereof. The method canfurther include introducing additional hot water to separate the bitumenfroth layer and solids.

In one embodiment, a method for extracting hydrocarbons from oil sandscan include: introducing water into a low-pressure vessel at about 20 toabout 40% of vessel capacity; heating the water to over 50 degrees C.and less than 120 degrees C.; introducing oil sands into the vessel at asolid/water volume ratio of about 0.1 to about 3 volume to form awater/oil sands mixture; closing and pressuring the vessel with a gas toa pressure of about 25 to about 210 psi; maintaining the temperature ofthe water/oil sands mixture between about 20 degrees C. to about 120degrees C.; decompressing the pressure in the vessel so as to generategaseous microbubbles that release the hydrocarbon from the oil sands;and recovering the hydrocarbon from the water and sands. Also, theprocess can be performed with at least one of the following: increasingthe pressure to a range of about 10 to about 150 psi followed byreducing the pressure by at least 10 psi; maintaining the temperaturebetween about 50 degrees C. to about 110 degrees C.; cycling thepressure for about 2 to about 30 pressure cycles; a solid/water volumeratio that is from 0.1:1 to 2:1; increasing the pressure at a rate ofcompression that is about 5 to about 300 seconds to reach maximumpressure; or decreasing the pressure at a rate of decompression that isabout 0.01 to about 300 seconds to vent to reach ambient pressure or anyother lowered pressure.

In one embodiment, a method for extracting hydrocarbons from sands caninclude: providing sands containing a hydrocarbon; mixing the sandcontaining the hydrocarbon with water; cycling the pressure of themixture in a vessel by increasing the pressure and then decreasing thepressure so as to change gas solubility in the water and form gaseousmicrobubbles in the mixture; and collecting the hydrocarbon from thewater and sands. The method can further include introducing a gas intothe vessel, wherein the gas is selected from the group consisting ofinclude ammonia, ozone, chlorine, air, nitrogen, oxygen, carbonmonoxide, carbon dioxide, argon, helium, water vapor, BF₃, CH₄, C₂H₂,C₂H₄, H₂S, C₂H₆, C₃H₆, propane, 1-butene, 1,3-butadiene, vinyl chloride,1,1,1,2-tetrafluoroethane, isobutane, n-butane, and sobutene andcombinations thereof.

These and other embodiments and features of the sensor device willbecome more fully apparent from the following description and appendedclaims, or may be learned by the practice of the sensor device as setforth hereinafter.

The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects, embodiments,and features described above, further aspects, embodiments, and featureswill become apparent by reference to the drawings and the followingdetailed description.

FIGURES

To further clarify the above and other advantages and features of thesensor device and compositions, an illustrative description of thesensor device will be rendered by reference to the appended drawings. Itis appreciated that these drawings depict only illustrated embodimentsof the sensor device and are therefore not to be considered limiting ofits scope.

FIG. 1 is a schematic diagram of an extraction system.

FIG. 2 is a graph showing the bitumen recovery efficiency (wt %) vs.cycle number, wherein the solid to water ratios are volume ratios, andthe separation vessel is pressurized to 100 psi by air.

FIG. 3 is a graph showing bitumen recovery efficiency (wt %) vs. cyclenumber, wherein the solid to water volume ratio is 0.5:1, and theseparation vessel is pressurized to 150 psi by air.

FIG. 4 is a graph showing bitumen recovery efficiency (wt %) vs. cyclenumber, wherein the solid to water volume ratio is 0.5:1, and theseparation vessel is pressurized to 100 psi by air.

FIG. 5 is a graph showing bitumen recovery efficiency (wt %) vs. cyclenumber, wherein the solid to water volume ratio is 0.5:1, and theseparation vessel is pressurized to 50 psi by air.

FIG. 6 is a graph showing the CO₂ pressurized hot water extraction ofbitumen from oil sands when CO₂ is at 100 psi compared to when CO₂ is at50 psi.

FIG. 7 is a graph showing the recovered bitumen at different pHconditions under overheated condition when the solid/water volume ratiois 1:1.

FIGS. 8A-8B are graphs showing bitumen recovery efficiency (wt %) fromCanadian high grade oil sands vs. cycle number when the solid to watervolume ratio is 0.5:1.

FIG. 9 is a graph showing bitumen recovery efficiency (wt %) fromCanadian low grade oil sands vs. cycle number when the solid to watervolume ratio is 0.5:1.

FIG. 10 is a graph showing the sand concentration (wt %) in theextracted bitumen at different temperature using different gases,wherein the solid to water volume ratio is 0.5:1 and the extractionpressure is 100 psi.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. In the drawings,similar symbols typically identify similar components, unless contextdictates otherwise. The illustrative embodiments described in thedetailed description, drawings, and claims are not meant to be limiting.Other embodiments may be utilized, and other changes may be made,without departing from the spirit or scope of the subject matterpresented here.

The present invention is drawn to systems and methods of removinghydrocarbons from solid samples. More specifically, the inventionrelates to processes and methods using a cyclicpressurizing-depressurizing gaseous treatment for extraction ofhydrocarbons from soil, sand, rock, and other solid samples.

A pressure cycling process can improve removal of hydrocarbons fromsamples, particularly fluidized sand samples. The pressure cyclingprocess can include the steps of pressurizing a fluid in a chamber withthe sample and depressurizing the fluid and sample for one or morepressure cycles. The fluidized samples can be prepared by combining ahydrocarbon-containing sand (e.g., tar sand or oil sand) and a suitablefluid, such as water. The fluidized sand sample and fluid arepressurized together and then depressurized in a cyclic manner so thatthe fluid causes the formation of microbubbles in the proximity ofhydrocarbons in the sand. In one aspect, the injection of a fluid into achamber with the sample can be performed simultaneously, and may resultin the pressurization, although sequential pressure cycling can also besuitable. After pressurizing, the sample is depressurized such that thefluid forms microbubbles in the sample proximal with the hydrocarbon.The microbubbles disrupt any solids within the sample in a mannersufficient to increase hydrocarbon separation efficiency from thesolids, such as sand and fines.

The pressurizing and depressurizing cycle can be repeated at least onceor any number of times that liberates a desired amount or percentage ofhydrocarbon. The pressurizing can be obtained by increasing the amountof fluid in the chamber, by reducing the volume of the chamber, or byincreasing the temperature in the chamber. The pressure cycle can beperformed at a substantially a constant temperature or within atemperature range, or the temperature can be varied along with thepressure.

The pressure cycling process can use liquids or gasses to improve theremoval of the hydrocarbons from oil sands or tar sands. The pressurecycling can include the steps of injecting the sand a liquid and/or agas, and then cyclically pressurizing and depressurizing the compositionso as to create microbubbles. The liquid and/or gas as well as the sandsample can be substantially devoid of a caustic compound that istypically used in hydrocarbon extraction from sands. For example, thepressure cycling process can be performed substantially without ordevoid of caustic compounds being selected from oxidizing agents, phasetransfer agents, and extraction agents. In another example, after thepressurizing, the sample can be depressurized to a second pressure whichis at least 10 psi lower than the first pressure. The pressure cycling,even without a caustic agent, can cause the sand particles to fractureand expose the hydrocarbon contained inside. The injecting,pressurizing, and depressurizing steps can be then repeated from 2 to100 times or more, depending on the particular system.

A. Definitions

As used herein, the term “slurry” or “slurry sample” refers to a liquidsample containing a solids content which is more than incidental solidsdebris. Although the percent solids can vary considerably, a slurrysample can have from 2% to 95% by weight of solids. High solids (e.g.20% to 70%) and low solids (e.g. 2% to 15%) slurries can be ofparticular interest in the present invention. Sand slurries can alsoinclude those substantially free of solids, e.g. non-slurry samples.

As used herein, the term “fines” is meant to refer to the smallparticulate nature of powders or silt in a sand particle or liberatedfrom sand that is less than 45 microns in size or less than 80 mesh. Assuch, the fines, such as sand fines or mineral fines, or other fines aresmall, finely divided, and light weight particulates that are easilyairborne when handled or exposed to minimal air currents. Such fines arealso susceptible to attachment to air bubbles, such as microbubbles.

I. Introduction

Hydrocarbon-containing sands (e.g., oil sands, tar sands, or bituminoussands) are a combination of clay, sand, water, and bitumen. The bitumenextracted from hydrocarbon sands has a similar chemical structure withconventional crude oil, but has higher density (e.g., a lower APIgravity) and higher viscosity. On average, bitumen from hydrocarbonsands contains 83.2% carbon, 10.4% hydrogen, 0.94% oxygen, 0.36%nitrogen, and 4.8% sulfur. Oil sands are found in over 70 countriesthroughout the world, and represent about 66% of the world's totalreserves of bituminous hydrocarbons. About 75% of the hydrocarbon sanddeposits are in Venezuela (e.g., 1.8 trillion barrels) and Canada (1.7trillion barrels). In the United States, hydrocarbon sands (e.g., oilsands and tar sands) are primarily concentrated in Eastern Utah and thesurrounding basin area, where the in-place bitumen content inhydrocarbon sand is estimated at be about 12 to 20 billion barrels.Presently, the United States has very little experience with producingoil from tar sands.

Previously, the bitumen in hydrocarbon sands has been attempted to beextracted both by mining and in situ extraction, including hot waterextraction process (HWEP), cold flow, cold heavy oil production withsand (CHOPS), cyclic steam stimulation (CSS), steam assisted gravitydrainage (SAGD), vapor extraction process (VAPEX), toe-to-heel airinjection (THAI), and closed-loop solvent extraction. Currently, theonly commercially operated hydrocarbon liberation and recoverytechnologies in Canada are HWEP and CHOPS for open-pit mines. Since allin situ extraction methods have to overcome two obstacles, 1) viscosityreduction of the bitumen and 2) recovery of the bitumen, most in situthermal methods, such as CSS and SAGD, are very energy intensive. VAPEXhas better energy efficiency since is similar to SAGD except that anorganic solvent is injected into the reservoir instead of steam. THAI isalso an in situ combustion method with much higher recovery efficiency,but it requires favorable deposit conditions and it will totally destroythe sands layer. Recent enhancements, such as tailings oil recovery(TOR) can recover oil from the tailings, diluent recovery units (DRU)can recover hydrocarbons from the froth, and inclined plate settlers(IPS) and the use of disc centrifuges, can recover over 90% of thebitumen in the sand.

The hot water extraction process (HWEP) has been commercially employedin order to recover bitumen from surface mined oil sands ore in hotwater. This technology utilizes the effects of ablation, mixing, massand heat transfer, and chemical reactions to separate and recoverbitumen from the sand and mineral particles. The hot water processcontains two steps: 1) liberation of bitumen from sand; and 2) recoveryof the liberated bitumen. The efficiency of separation by HWEP isgreatly affected by the addition of caustic reagents and otheradditives.

Also the fines content of oil sands affects recovery efficiency. Oneproblem with HWEP is the high costs of liberation and recovery ofbitumen. As such, a reduction in the slurry temperature could be costeffective. However, the lower temperatures result in longer conditioningtimes and require more additives, and have complicated this process.

In HWEP, a composition of hydrocarbon sand and hot water is conditionedfor liberation of bitumen in batch tumblers or conditioning drums. Also,the hydrocarbon sand can be conditioned during transportation from thequarry by combining the sand and water into a slurry mixture fortransportation in a pipeline to the extraction plant. The blended slurryis settled into three layers in a primary separation vessel (PSV) aftergas floatation: impure bitumen froth on the top; a combination ofbitumen, sand, clay and water in the middle (middlings); and sand to thebottom. The sand precipitate cam be pumped into settling basins withwater, which is called tailings. The middlings are further separated andcleaned by air injection and steam de-aeration, respectively. The HWEPrequires two to four barrels of water for each barrel of oil. Onaverage, less than 75% bitumen can be recovered from oil sands by HWEP.It has been shown that ORS (e.g., organic rich solids—toluene insolubleorganics directly absorbed onto particle surface) fraction inhydrocarbon sands is an impediment to for bitumen separation andrecovery. Also, the clay fines and polar organics can cause poor bitumenseparation and recovery.

The selection of recovery and treatment processes of different oil sandsdeposits are influenced by the properties and composition of the oilsands and the bitumen. Since Canadian Alberta oil sands contains moremoisture than Utah oil sands, optimal extraction methods for Utah oilsands are likely to be different from those in Alberta. Since Utah oilsands are different from Canadian oil sand, HWEP is inefficient for Utahoil sands. Attempts to increase the efficiency of liberation andrecovery for Utah oil sands have modified the HWEP process to providemore intense shearing forces and more caustic wetting agents, such assodium hydroxide, due to much higher viscosity of bitumen in the Utahoil sands. In response to the problems with HWEP and the nature of Utahoil sands, the pressure cycle process of the present invention can beused in order to enhance recovery of bitumen from oil sands, especiallyfor Utah oil sands.

Accordingly, the present invention includes an improvement in bitumenliberation and recovery by introducing pressure cycling to theliberation and recovery process. For example, any of theabove-references liberation and recovery processes, such as HWEP, can bemodified to include a pressure cycling process that increases thepressure of a fluidized oil sand sample, and then releases the pressureso as to obtain a decompression pressure drop that forms microbubblesand introduces shear forces to the bitumen and sand interface. Thepressure cycling can be adapted to various processes by preparing afluidized oil sand sample, and then performing the pressure cyclingprocess.

II. Pressure Cycle Bitumen Extraction

The pressure cycle process is an improvement over conventional heated orhot water extraction of oil sands by modulating the pressure of thesample by increasing and decreasing the pressure of the sample throughpressure cycles (e.g., 10 to 100 psi cycles). The pressure cycles resultin dissolution of gas into water during the compression stage andsubsequent degassing via microbubble formation during the decompressionstage. The pressure cycle process improves the conventional hot waterextraction of bitumen so as to be faster with a higher-yield, and ismore economical. Additionally, the pressure cycle allows for bitumenextraction at lower temperatures than previously obtained and with theuse of many different gases. The pressure cycle process is an importanttool for developing oil sands for which energy consumption and wateravailability are critical concerns, such as the Utah oil sands.

The creation or presence of gaseous microbubbles and even nanobubbles inthe processing of oil sands can enhance the liberation and recovery ofthe entrapped hydrocarbons. In part, the presence, generation, oramplification of gaseous microbubbles enhances the extraction ofhydrocarbons from sands because: a) microbubbles provide abundantinterfacial surface areas that acts as a detergent film to collectbitumen, resulting in their efficient collection; b) the formation ofgas bubbles in the space containing bitumen pries open bitumen-coatedsand grains, helping to release the bitumen; and c) gaseous microbubblesserve to lift the separated bitumen, thus performing the separation andfloatation collection in a single step. The use of different types ofgases can modulate the rate, efficiency, and total amount of hydrocarbonrecovery.

An improved bitumen liberation and recovery process employs cycliccompression and decompression of oil sands in the presence of a fluidthat can generate gas bubbles. For example, sands can be prepared into aliquid slurry in a separation vessel, gas can be injected into theseparation vessel to increase the pressure, and then the pressure can bereduced. The gas can be air, carbon dioxide, or other suitable gas. Thepressure cycle process can accelerate the displacement and disengagementrates of bitumen from oil sands. The pressure cycles can provide anaction on the bitumen in the sands similar to the use of mechanicalagitation and/or caustic reagents, without the requirement of usingmechanical agitation or caustic reagents. A pressure cycle processperformed with a water temperature that is higher than the boiling pointat atmospheric pressure (e.g., 100° C., 1 atm) during air compressionprocedure can provide even more liberation and recovery efficiency. Thepressure cycle process can be performed with or without intenseagitation, caustic reagents, and other additives. The pressure cycleprocess can provide for more than about 95% bitumen liberation andrecovery in a short time period.

The pressure cycle process takes advantage of the high heat and masstransfer rates, quicker chemical reaction rates such as hydration ofquartz, mixing, lower viscosity, and ablation during decompression. Theenergy density per unit volume to treat oil sands obtained bydecompression can be much higher than the energy density of mechanicalagitation because the potential heat is released in a short time, andoptionally under a overheated condition (e.g., over 100° C.). When CO₂is injected into water instead of air, recovery efficiency of bitumenstill can be as high or higher than about 85%, but at much lowertemperature. Also, because the pressure cycle process combines theseparation procedure and recovery procedure together, the totalprocessing time is much shorter than processing time of convention HWEP.

Most of the hot water used in the pressure cycle process can be quicklyrecycled due to the fast separation of solids from hot water. Since thepressure cycle process is conducted in a batch reactor, it is moreflexible and practical, especially for small deposits and/or Utah oilsands deposits. Additionally, the equipment requirements, such as thoseshown in FIG. 1, are less than conventional HWEP requirements becausethe separation vessel and recovery vessel are combined together.Moreover, the relatively low elevated pressure does not need special,expensive equipment.

The pressure cycle process can be applied on different kinds and gradesof oil sands, such as Canadian and Utah oil sands. In part, this isbecause the separation efficiency is more reliable than other hot waterprocesses, and can allow for the oil sands to have different finesconcentrations and different viscosities of the liberated bitumen. Thisprocess can lower the cost and has much lower contaminant concentrationsin the discharged water and solids (e.g., tailings). Thus, mostenvironmental problems associated with tailing are avoided.

Preliminary studies have shown that the pressure cycle process cangreatly simplify the operating procedure of bitumen recovery from oilsands by combining the separation step and floatation step together andbeing performed without using any chemical additives. Thecompression/decompression process leads to displacement anddisengagement of bitumen from sands without requiring intensiveagitation, which is especially desirable for Utah oil sands and can beemployed with any oil sands.

Additionally, the pressure cycle process can be a more environmentallyfriendly in the liberation and recovery of bitumen. In part, this isbecause the pressure cycle process can avoid the subsequentenvironmental problems caused by caustic additives and the presence ofhydrocarbons in water that are difficult to separate. The pressure cycleprocess is efficient even when no caustic reagents or other chemicaladditives are added. The pressure cycle process does not emulsifybitumen in aqueous phase, and thereby the recovery efficiency isincreased.

In addition, the pressure cycle process has a much higher separationrate compared to conventional HWEP because the liberation step andrecovery step are combined into a single step. For example, if a gas,such as carbon dioxide, is injected in a separation vessel with aslurried oil sand, even at much lower temperature (e.g., <55° C.), thepressure cycle process can still recover more than about 90% bitumen.High recovery efficiency can be achieved due to high solubility ofcarbon dioxide in water and in hydrocarbons at relative lowtemperatures, which solubility can be increased with increased pressure.Also, the pressure cycle can disrupt the physical structure of the sandand expose more bitumen for liberation. Since conventional gases, suchas carbon dioxide, can be recycled, the energy cost of the pressurecycle process can be much lower than the cost of a conventional hotwater process, such as WHEP.

Bitumen can be obtained from hydrocarbon sand by using pressure cyclesto obtain the following: good liberation of bitumen from sand grains;good attachment of bitumen to an air bubble; and flotation of theaerated bitumen (e.g., bitumen on air bubble). In addition to or inconjunction with pressure cycle process described herein, bitumenliberation from sands can be enhanced by increasing: mechanical shear;water addition ratios; mechanical energy input levels; chemical additionlevels; temperatures; residence times; the base (NaOH) addition amount;surface surfactant to affect the interfacial properties of the bitumenand the sand grains; and aeration of the hydrocarbon-sand slurry.

High content of clay fines in the bitumen extraction process is notfavored because the surface of bitumen and air bubbles can be covered bythe fines, and the probability of adequate bitumen-air bubble attachmentis reduced. The presence of divalent ions further aggravates thissituation, and reduces recovery of hydrocarbons. After the bitumen isliberated from the sand, a good flotation environment can increasebitumen recovery. A good chemical additive can improve bitumen recoveryand at the same time to act as a good flocculent for the fines, such asan optimal concentration, hydrolyzed polyacrylamide (HPAM) can improveboth bitumen recovery from oil sands and fines settling. Other means ofincreasing the settling and precipitation of fines can also be used toreduce fines content.

When the temperature of water is heated above its boiling point atatmospheric pressure (e.g., above 100° C., 1 atm), the operationcondition is defined as an overheated condition. Although the water doesnot boil at elevated pressure (e.g., 50-150 psi), the water isoverheated and will spontaneously boil when the pressure is released. Itis believed that the expanding and shearing forces caused bymicrobubbles and other effects due to decompression of overheated watercan accelerate displacement of bitumen from the surface of oil sands.Also, the coagulation and rising of microbubbles can coagulate and bringbitumen droplets to the surface to generate bitumen froth.

The recovery of bitumen can be influenced by the overheated temperatureand decompression rate. Higher temperatures can release more potentialheat, but more energy is required to heat the vessel. Fast decompressioncan separate bitumen more quickly, but the recovered bitumen may containmore solid and moisture.

In one embodiment, the present invention can provide a method ofremoving hydrocarbons from fluid samples, particularly slurry samples ofoil sands. The method can include pressure cycling a slurry of oil sandand a fluid that is capable of generating bubbles during decompression.As such, the method can include the steps of pressurizing the sample,injecting the sample with a gas, and depressurizing the sample. Thesample can be pressurized by directly injecting the gas into the sample.Accordingly, a slurry sample can be compressed and then decompressed toliberate and recover hydrocarbons from oil sands. As such, separatepressurization and injection are not necessary, and can be conducted inone single step. For example, a fluid sample of hydrocarbon sand can beprepared prior to pressurizing with air only or other gas. Afterpressurizing, the sample can be depressurized such that the gas formsmicrobubbles in the sample. The microbubbles disrupt the hydrocarbonfrom the solids within the sample in a manner sufficient to increasehydrocarbon separation efficiency. The pressurizing and depressurizingsteps can be repeated at least once. Optionally, the pressure can beincreased by reduction of volume or increasing temperature when a gas ispresent with the slurry sample.

The duration of each of the pressurizing and depressurizing steps can bevaried based on a number of factors including, but not limited to, thenature or quantity of the sample, the magnitude of hydrocarbon of thesample, the type of gas being used, the change in pressure during eachof the pressurization or depressurization steps, and the like.

The pressurizing and depressurizing steps can have a time durationvarying from seconds to minutes for the individual steps depending onthe particular system of sand, hydrocarbons, and gases. The rate ofcompression can be between about 5 seconds and about 300 seconds orlonger, more preferably between about 10 seconds and about 200 seconds,and most preferably between about 15 seconds and about 100 seconds. Therate of decompression can be between about 0.01 seconds and about 300seconds, more preferably from about 0.1 seconds to about 200 seconds,and most preferably between about 1 second to about 100 seconds. Anoptimal cycle can include compression and decompression steps that areperformed as fast as possible.

The number of repetitions of the pressurization, injection, anddepressurization steps (e.g., pressure cycle) can also be varied from 1to 30 cycles, 1 to 100 cycles, or more. In one embodiment the number ofrepetition of the pressurization and depressurization steps can be atleast 3 cycles, such as from 3 to 15 cycles. As a guideline, optimaltime duration and number of decontamination cycles can be readilydetermined for each sample based on monitoring and/or testing.

The pressure cycle process can be performed at a variety of temperaturesranging from room temperature to overheated water temperatures. Also,the pressure cycle process can operate with a reduced temperaturecompared to HWEP. The processing temperature can be between about 20° C.to about 120° C., more preferably from about 30° C. to about 105° C.,and most preferably from about 55° C. to about 80° C. Gases such ascarbon dioxide with high water solubility can be functional at lowertemperatures (e.g., 20° C. to about 50° C., more preferably from about30° C. to about 40° C., and most preferably from about 35° C. to about80° C. Gases such as air, oxygen, or nitrogen as well as gases such ascarbon dioxide and other highly soluble gases can be functional athigher temperatures (e.g., 50° C. to about 120° C., more preferably fromabout 75° C. to about 115° C., and most preferably from about 95° C. toabout 110° C. The optimal extraction temperature can be identified by adetermination of other conditions such as compression/decompressionpressure, stirring intensity, and gas composition and quality of oilssands. The temperature can also be lowed when more pressure cycles areemployed. Higher pressure and temperature can use few pressure cycles,especially for water heated higher than its boiling point under ambientpressure. The pressurized cycles can greatly accelerate separation ofbitumen from sands due to lower bitumen viscosity and higher density ofmicro bubbles generated during decompression procedure.

The depressurizing step in the pressure cycle process can result in anypressure reductions sufficient to create microbubbles. Typically, thepressure cycle range can be a change in pressure from about 10 psi toabout 1000 psi, and more preferably from about 10 psi to about 500 psi,and most preferably between 10 psi and 200 psi, although pressure dropsoutside this range can also be suitable. In another embodiment, thepressure reduction during the depressurization step leaves the sample atambient pressure.

In one embodiment, the pressure can range between about 10 psi to about210 psi, more preferably 25 psi to about 175 psi, and most preferablyabout 40 psi to about 150 psi.

The solid concentration in the extraction medium can have a solid/watervolume ratio of about 0.01 to about 3, more preferably about 0.1 toabout 2, and most preferably 0.1 to about 1. For example, the solidwater volume ratio can be from 0.1:1 to 2:1, especially from 0.2:1 to1:1.

The extraction pH can be controlled from about 2 to about 12, morepreferably from about 3 to about 11, and most preferably from about 5 toabout 10. The pH can be controlled by adding acids, such as HCl(hydrogen chloride) and acetic acid, or caustic reagents, such as NaOH(sodium hydroxide) and Na₂CO₃ (sodium carbonate), into the water oilsands mixture, or be allowed to change without control. Also, the pH ofwater can be affected by the gas compositions such as when CO₂ ispressurized into the water and oil sands mixture during compressiondecompression cycles.

In one embodiment, the process for the removal of hydrocarbons from ahydrocarbon-containing sample can be further aided by some form ofagitation during at least one of the steps of pressurizing ordepressurizing. Examples of agitation means include, but are not limitedto stirring, shaking, ultrasound, and the like. It is noted multiplemeans of agitation can be combined during any given step of hydrocarbonextraction. Agitation can also be sufficiently achieved solely viadegassing and movement of microbubbles during the depressurizing stepwith significant energy savings.

The stirring intensity of the water and oil sands mixture is anotherimportant parameter that can be regulated. The optimal stirringintensity is decided by the extraction vessel size, configuration of theagitator, solid loading, bitumen viscosity, extraction temperature andother parameters. Good mixing of oil sands and water can increaseextraction rate and enhance bitumen quality. In this implementation, thestirring rate or equivalent agitation by bubble formation can be betweenabout 0 rpm and about 1000 rpm, more preferably between about 10 rpm toabout 600 rpm, and most preferably between about 30 rpm and about 120rpm. Agitation provided by liquid motion brought by compression anddecompression cycles, with or without additional means, is possible.

The pressure cycle process can be performed with various gases that arepressurized with the oil sands and hot water bath by compression.General examples of gases include air, O₂, N₂, CO₂, methane, ozone,noble gases, combinations thereof, and the like. The gas can beintroduced into the fluid sample at different times, although in eachscenario the gas must be in contact and preferably dissolved at leastpartially in the fluid sample before decompression is to proceed. It maybe important in some instances for the gas and the fluid sample tocontact and reach some degree of dissolution prior to decompression.

In one embodiment of the present invention, the gas can be added to thefluid sample before the pressurizing step. In another embodiment, thefluid sample can be injected with the gas during or after thepressurizing step. In another embodiment, the repetition of thepressurizing step and the depressurizing step can be performed withoutrepetition of injecting additional gas. Additionally, when repeated, thepressurizing step can result in a different pressure increase whencompared to the initial or first pressurizing step. Similarly, whenrepeated, the depressurizing step can result in a different pressurereduction as compared to the initial depressurization step. Thus, thecycling of pressure can have varying high and low pressures or can havesubstantially the same high and low pressures. In one aspect of theinvention, the fluid sample having the hydrocarbon can be heatedsufficiently so that the sample can be super saturated with the gas.

The nucleation and growth of microbubbles, which occurs at theenergetically favorable (e.g., non-wetting) surface of particulatematter, can accelerate the extraction of the hydrocarbon. Duringdepressurization, microbubbles appear at the particulate surfaces in theliquid phase. The various sizes of microbubbles can vary continuallyfrom their initial formation in a sub-nanometer (<1 nm) range through avisible range (e.g., <1 mm) in their final coalescing into large bubbles(e.g., <1 cm) that rise rapidly to the water surface. The concentrationof bubbles as well as the duration of their appearance depends on thedegree of saturation with the gas, which in turn depends on the pressureemployed, and the volumes of liquid and available headspace. A largeamount of dissolved gas at high pressure will support more extensivebubble formation during depressurization, and the rate of growth of thebubbles along with the duration of the bubbles are controlled by therate of depressurization. In addition, the rate, duration, and pressureemployed during pressurization will determine the level of saturation.Thus, the pressure, pressurization rate, and depressurization rate canbe fine tuned to support the concentration and duration of microbubbles,thus the abundance of reactive interfacial zone, for optimal hydrocarbonextraction.

A variety of gases can be used in the methods of the present invention.Non-limiting examples of suitable gases can include ozone, chlorine,air, nitrogen, oxygen, carbon monoxide, carbon dioxide, argon, helium,water vapor, and the like. Mixtures of gases can also be used in theinvention. The elevated pressure applied during the pressurizing stepcan enable the dissolved gas to effectively penetrate the pores ofparticulate matter in a slurry sand sample or can cause liquefaction.Particulates and agglomerations of debris often shield hydrocarbons intar sands. When the gases have penetrated the particles and expandduring the depressurizing step, they can cause the solid particle toexplode, partially disintegrate, or at the very least cause the pores ofthe particulate matter to expand thus enhancing the exposure ofhydrocarbons.

In one embodiment, the gas for use in the compression/decompressioncycles is comprised of carbon dioxide (CO₂). The use of a CO₂ assistedpressure cycle extraction process can decrease energy costs associatedwith the use of hot water in the separation process. The CO₂ assistedpressure cycle extraction process can be used at a greater rage oftemperatures. Also, CO₂ solubility decreases dramatically whenapproaching the water boiling point, and higher pressures and/or morecycles may be used for desirable extraction. If the water temperature ishigher than its boiling point under normal pressure, the CO₂ assistedpressurized extraction process can function similarly to the overheatedhot water extraction process that uses air. It has been found thatcarbon dioxide is exceptionally efficient for use in separating bitumen(e.g., hydrocarbons) from tar sands. Also, the use of carbon dioxideallows for lower temperatures and pressures with increased efficiency.For example, the temperature for use with carbon dioxide can be as lowas 55 degrees and a low pressure of 50 psi. The separation andextraction of hydrocarbon from tar sands is very good. Instead of using85° C. or above, the separation can now be performed at a very lowtemperature, and instead of using 150 psi or 100 psi the hydrocarbon canbe separated using a pressure as low as 50 psi, and in some instances aslow as 40 psi, and in other instances as low as 30 psi.

Additionally, with carbon dioxide as the gas, the temperature can bereduced to below 50° C. to about 40° C., more preferably to about 30°C., and most preferably to about 35° C. or room temperature. Thereduction in temperature changes the viscosity of the bitumen. Bitumenchanges from being fluidic at very hot temperature to being more solidat cold, low temperatures. The low temperature changes the viscosity ofbitumen and hydrocarbons in general. It is thought that the coldtemperature processing can be efficient when used in multiple cycles.

In one embodiment, the gas can be substantially pure carbon dioxide.Also, the gas can be a mixture of carbon dioxide and another gas, suchas air, nitrogen, oxygen, noble gas, ozone, carbon monoxide and thelike. The percentage of carbon dioxide can range from about 10% to about100% (volume percentage), from about 20% to about 90%, from about 30% toabout 80%, from about 40% to about 70%, and from about 50% to about 60%.

The gas may also be a combination gas having CO₂ mixed with another gas.Since the overheated condition can generated more gas bubbles duringdecompression by vaporization of water itself, the recovery rate ofbitumen with CO₂ can be faster. Also, the compression of a morewater-soluble gas, such as CO₂, into a hot water and oil sands mixturecan have higher separation and recovery rate. Theoretically, most gasesthat are more soluble in water than air can be used, such as NH₃, Cl₂,and CO₂. However, solubility of the gas should be someone limited so asto no be too high. Otherwise the gas has to be recycled from water afterextraction and the process may need additional operation procedures.Also, the gas should be inert so as to avoid reacting intensively withbitumen or water. Since some gases, such as CO₂, may have somereactivity with water and carbons, the reactivity of the gas with thewater and with the hydrocarbon should be as low as possible, andpreferably nonreactive. In a practical application, CO₂ could be themost economic choice. In commercial oil sands extraction, water isheated by burning natural gas or other fuels, and the CO₂ that isproduced during combustion of fuels can be a potential resource of CO₂.External CO₂ can be used because recycling of the released CO₂ is notcomplicated, and the consumption rate of CO₂ is negligible.

Based on air and CO₂, other gases with similar solubility as air or CO₂or higher solubility than air or CO₂ in aqueous phase, or has highersolubility in bituminous phase than air or CO₂, potentially can be usedfor pressurized hot extraction of bitumen from oil sands. Examples ofsuch other gases can be Ar (5.2 ml per 100 g water at 0° C., 2.2 ml per100 g water at 50° C.), BF₃ (106 ml per 100 g water at 0° C.), CH₄ (5.56ml per 100 g water at 0° C., 1.772 ml per 100 g water at 80° C.), C₂H₂(173 ml per 100 g water at 0° C.), C₂H₄ (22 ml per 100 g water at 0°C.), C₂H₆ (173 ml per 100 g water at 0° C., 1.72 ml per 100 g water at100° C.), H₂S (467 ml per 100 g water at 0° C., 81 ml per 100 g water at100° C.), O₂ (4.89 ml per 100 g water at 0° C., 1.72 ml per 100 g waterat 100° C). , N₂ (2.35 ml per 100 g water at 0° C., 0.95 ml per 100 gwater at 100° C.), C₃H₆ (propylene, 43.4 ml per 100 g water at 0° C., 23ml per 100 g water at 20° C.), C₃H₈ (propane, 3.9 ml per 100 g water at0° C.), 1-butene (8.5 ml per 100 g water at 20° C.), 1,3-butadiene (45ml per 100 g water at 21° C.), vinyl chloride (131.5 ml per 100 g waterat 20° C.), 1,1,1,2-tetrafluoroethane (21 ml per 100 g water at 25° C.),isobutane (3.25 ml per 100 g water at 20° C.), n-butane (3.25 ml per 100g water at 20° C.), and isobutene (16.59 ml per 100 g water at 20° C.).Mixtures of the above two gases or more than two gases, including airand carbon dioxide, also can be used for pressurized hot water processextraction. Also, internal combustion engine exhaust, turbine engineexhaust, and exhaust from furnace or boiler can be input into theseparation vessel for pressure cycle bitumen extraction.

For gas mixtures such as air/CO₂ mixture and N₂/air/CO₂ mixture, the CO₂concentration can be from 1% to 99% by volume, especially from 15% to50% by volume. Other gases such as Ar, BF₃, CH₄, C₂H₂, C₂H₄, H₂S, C₂H₆,C₃H₆, C₃H₈, 1-butene, 1,3-butadiene, vinyl chloride,1,1,1,2-tetrafluoroethane, isobutane, n-butane, and isobutene or anymixtures of the above gases can be used as the extraction gas.

Sand samples which can be treated by the method of the present inventiongenerally have a solids content of from 2% to 95% by weight. In oneembodiment, the slurry sample has a relatively high solids content offrom 35% to 50% by weight. High solids content slurries can range fromflowable slurries to thick pastes. In each case, treatment and handlingcan differ, although application of the present invention can beeffective to remove hydrocarbons from such samples. In anotherembodiment, the slurry sample has a relatively low solids content offrom 2% to 15% by weight. The solid components of the slurry samples canbe from any environmental source, such as sand or dirt, so long as thesolid components can take the form of a slurry or be suspended in afluid.

In one embodiment, a pressure cycle process can extract hydrocarbonsfrom a sample by at least 50%, more preferably from about 50% to about100%, most preferably from about 75% to about 99%, and most preferablyfrom about 85% to about 95%. In an alternate embodiment, a process asdisclosed herein extracts the hydrocarbon from the sample by at least90%. In an alternate embodiment, a process as disclosed herein extractsthe hydrocarbon from the sample by at least 95%. In an alternateembodiment, a process as disclosed herein extracts the hydrocarbon fromthe sample by at least 99%. In an alternate embodiment, a process asdisclosed extracts the hydrocarbon from the sample by at least 99.9%.

An illustration of a pressure cycle bitumen extraction assembly of theinvention is presented in FIG. 1, which shows separation vessels 20, 30for an extraction of hydrocarbon from oil sands. The use of two vessels20, 30 allows for the simultaneous liberation and extraction of two oilsand samples in parallel. This can include one vessel 20 being incompression while the other vessel 30 is in decompression, and the gasfrom one being transferred to the next. Also, new gases or newlyrecycled gases can be used for both vessels. Of course the multiplevessels can be run on the same compression and decompression pattern.While two vessels are shown, the extraction assembly can be used withonly one vessel 20. Alternatively, the extraction assembly can be usedwith three or more vessels. The material used to construct vessels 20,30 is stainless steel, as it is able to withstand pressure. However,other suitable materials will be readily apparent to one of ordinaryskill in the art and may be varied according to an application of aprocess of one embodiment of the invention, such as, but not limited toa various metals and alloys, thermoplastic polymer, rock, a geophysicalformation, ceramics, composites, combinations thereof, and/or the like.

Various embodiments contemplate the use of one vessel with or without areturn loop, and/or other multiple vessels, and/or return loops toincrease a potential number of cycles. Likewise, further embodimentscontemplate separate vessels for the same or different extraction ofhydrocarbon from at least one sample in parallel or in series. In suchan embodiment, two or more vessels can be used to extract hydrocarbonfrom the sample with one or more solvents (e.g., water) after thecompression/decompression cycle.

Returning to the illustrated embodiment of FIG. 1, a vessel 20 isconnected to at least one valve 40, two valves in this embodiment 40,45, 50, and 55, for vessel 20 and vessel 30.

Valves 40, 45, 40, and/or 55 may be any valve common in the art, such asa ball valve, piezo electric valve, hydraulic valve, and/or the like. Invarious embodiments, valves 40, 45, 50, 55 can be used for inlet for thegas and/or fluidized sand sample. Various embodiments connect a supplyof gas 60 to the extraction assembly. Further embodiments contemplatethe use of multiple gases and/or multiple sources of various gases.

Further embodiments incorporate regulating valves 5, 15, which act asexhaust valves for relieving pressure from the vessel 20, 30. A meshmaterial 25, 35 or screen, such as an aluminum mesh can optionally beplaced at the bottom end of vessel 20, 30 to support solids in thesample. Other embodiments use a shelf, net, or other supportive materialcan be used to support the sample.

A pressure gauge 1, 11 is mounted about an upper portion of each vessel20, 30 to measure the pressure inside each vessel 20, 30. The range ofpressure may vary and can be selected as is suitable for the particularprocess, taking into account such parameters as the material from whichthe reactor assembly is constructed, the number of cycles to beperformed, the solvent used, the fluid used, the constituents of thesample, and/or the like.

In one embodiment, the method can be accomplished in a separation vesselhaving two (2) stainless steel pieces, which are attached to form thereactor. In various reactors, vents, inlets, outlets and the like may bearranged about the reactor as needed for the application. Further,various reactors can work as a batch or as a flow reactor with respectto the slurry, and as a flow reactor with respect to a gas mixture.

In an industrial application, the oil sands can be mixed with recycledheated or hot water, and then pumped into the extraction vessel. Also,additional oil sand can be added into the vessel. The additional oilsands can be advantageous in instances where the pump cannot transferhigh solid concentration mixture into the separation vessel, suchas >1:1 volume ratio. Alternatively, additional water or gas can beintroduced into the separation vessel.

The extraction assembly can include a device on the top of theseparation vessel to collect bitumen once bitumen and oil sands havebeen separated. Thus, the industrial process for removal of bitumen canbe included automated equipment and devices known in the petroleumindustry to obtain the upper fractions of the separation depending onbitumen content.

Although steam can be used to heat the mixture, other methods, such as aheating jacket or heat coil, can also be used to increase or maintainthe temperature in the separation vessel. Methods of heatingcompositions are well known, and about any of such teaching methods canbe used in the present invention. In previous methods, the compositionswere heated to high levels. Now, with the use of carbon dioxide andsimilar gases the extraction of oil sands can be employed with heatedwater that is substantially below the boiling point.

Additionally, Utah bitumen separated form oil sands contains less sulfurin comparison with Canadian wet oil sands, and thereby this process canbe useful for extraction of hydrocarbons that have less sulfur as wellas those sands that have more sulfur.

The pressure cycle process of the present invention is advantageous fornumerous reasons. For example, the formation of microbubbles can provideabundant interfacial regions near the gas-hydrocarbon-solid, whichprovide favorable partitioning zones for extracting hydrocarbons.

Another advantage is the repetition of the pressurizing anddepressurizing of the sample to cause the sand particles to fracture andexpose the bitumen. The repetition of these steps provides enhanceddegradation of the solid particles, and thereby enhanced hydrocarbonextraction efficiency due to the increased exposure of the hydrocarbon.The elevated pressure caused by the pressurization step enables the gasto effectively penetrate the pores of particulate matter that oftenshields hydrocarbons in sand. The pressure cycle process provides higherproduct yield compared to the conventional HWEP.

The increase in pressure also causes oversaturation of the dissolved gasin water such that when the pressure is released, it results indegassing of the water and microbubble formation. The oversaturation ofthe slurry sample with gas and subsequent degassing can enhance theability to remove the hydrocarbon from the sands. Also, thepressurizing/depressurizing process creates an abundance of gaseousmicrobubbles that can have enhanced interaction with the hydrocarbonwithin the sands and provides for the hydrocarbon to be liberated fromthe sands. Thus, cyclic gas solubility changes in the process aide inextracting the hydrocarbons from the sands.

Additionally, the pressure cycle provides easier product separationcompared to convention HWEP. The decompression results in countlessgaseous microbubbles that provide a huge surface area at the gas-liquidinterface that attracts and gathers hydrophobic bitumen, effectivelyseparating and lifting the bitumen globs to the water surface forcollection (i.e., the flotation effect).

The pressure cycle process can save energy compared to conventionalHWEP. Due to enhanced bitumen liberation by the microbubbles, lowerwater temperature can be used for higher yield, which results in energysaving that more than compensates the minimal energy expended incompression with gases.

The pressure cycle process can obtain superior bitumen extraction in ashorter process time compared to HWEP. The rapid pressure cycles cutdown contact time between tar sands and heated or hot water. Data hasshown that greater than 90% yield of bitumen within 5 min is possible.When using CO₂ from a gas tank, each cycle can take several seconds. Assuch, extraction of bitumen by several cycles can take only severalminutes. For a large vessel, the bitumen floatation procedure can belonger because the floatation path is longer than in a small vessel.Thus, the gas compressor capacity, vessel size, and solid loading candetermine the total operation time. For example, the CO₂ pressure cycleprocess can yield 90% bitumen in 10 cycles in 5 minutes. In comparisonto extraction without the pressure cycles, the same yield requires 3hours of contact with hot water and under mild agitation (or underintense agitation).

The pressure cycle process is useful for a larger variety of differenthydrocarbon sands compared to HWEP. HWEP was shown to be insufficientfor Utah oil sands. However, the pressure cycle process can be used forextraction of Utah oil sands that are oil wet; unlike Canadian's waterwet oil sands, the oil wet property is an impediment to effectiverecovery by conventional hot water extraction method. Thus, this is anew tool for developing Utah's unique, rich oil sands resources.However, the process can be used for liberating any oil from anymaterial.

Complete extraction of bitumen is viable with the pressure cycle processat high solid concentration (e.g., up to solid/water ration of 1.5/1).This reduces the volume of process water, for which water availabilityis a critical issue in arid Utah where oil sands are found. A reductionin process water volume means less process water that requires treatmentprior to disposal or reuse.

Additionally, a tailing pond is not necessary for the pressure cycleprocess. This can reduce the environmental problems that are caused bythe discharge of solid and processing water because no additives areadded. The COD of water recycled from air pressurized hot waterextraction process is 95±5 mg/L, while COD of water recycled from CO₂pressurized hot water extraction process is only 47±3 mg/L (<20 mg/Lorganic carbons). This is because CO₂ dissolved in water can preventsome acidic hydrocarbons from dissolving into water. Also, theprocessing water can be directly discharged because the hydrocarbonconcentration is much lower than the discharge limitations. Thus, thepressure cycle process can solve the problems caused by hot waterprocess currently commercialized in Canada, which requires huge amountof water and consumes lots of energy, and need large tailings pond.

Experimental

1.

The pressure cycle process can be conducted by dramatically increasingand then decreasing the pressure. Briefly, in a low-pressure bitumenseparation vessel with mechanic agitation (e.g., 175 psi grade reactor),1 volume of water (e.g., 20-60% of vessel capacity) is added into thebitumen recovery vessel. After the water is heated to over 50° C. byinjecting steam into the aqueous phase or by a heater, 0.1-1.5 volumeoil sands are added into the vessel. After all oil sands are added intothe vessel, the vessel is closed and pressurized to 50-50 psi. The gascan be air, nitrogen, CO₂, or other non-reactive gas or mixtures ofthem. Temperature of the water/oil sands mixture is controlled between50° C.-105° C. The elevated pressure in the vessel, 50 psi-150 psi, canprevent boiling of water if the temperature is higher than water boilingpoint under normal pressure. The dissolved gas in aqueous phase cangenerate micro bubbles during decompression.

After the water temperature is adjusted to the set temperature, thepressure in the vessel is released through a valve installed on thebitumen extraction vessel. When the temperature is lower than waternormal pressure boiling point, the pressure can be quickly released tonormal pressure by totally opening the releasing valve. Theoversaturated gas in aqueous phase can generate micro bubbles duringdecompression procedure. If before pressure releasing, the water and oilsands mixture is heated over water normal pressure boiling point, thepressure releasing rate is controlled by the openings of the releasingvalve to prevent bitumen being taken out by the rush of water vapor. Thebitumen floated is collected and dried to measure the weight.

Visual analysis of the products obtained from the separation shows theseparation and floatation of bitumen in the vessel after decompression.In the visual analysis it was observed that 1) bitumen can be extractedfrom the oil sands, and 2) the process water and settled sands aresignificantly reduced of hydrocarbons and lack a black color while theextracted bitumen is thick like crude oil. The compression anddecompression procedures can be repeated any number of times becausemore compression/decompression cycles can separate more bitumen from oilsands.

The recovery of bitumen from oil sands with a pressure cycle processindicates that the separation of bitumen from oil sands is significantlycontributed by the decompression step. The decompression step releasesthe accumulated potential energy from the heat energy, and the intensiveshearing force and high chemical reaction rate achieved duringdecomposition of overheated water accelerates separation and coagulationof bitumen. The microbubble floatation effect induced by decompressionalso accelerates the recovery of bitumen. The lower viscosity of bitumenunder higher temperature may also be an important aspect for bitumenrecovery.

2.

The number of compression/decompression cycle number can be affected bysolid loading amount and extraction temperature. The volume ratio ofwater to oil sands can larger than 2, which can leave enough space forbitumen froth generation and floatation. In order to increaseefficiency, higher oil sand loading was studied. If the water level inthe vessel is not high enough for bitumen froth generation (e.g.,solid/water ratio>1) after bitumen is separated from oil sands,additional hot water can be added into the reactor to further separatethe bitumen froth layer and solids.

The experimental results shown in FIG. 2 show that more cycles canextract more bitumen, but for energy consideration and processingcapacity optimization, 4-6 cycles are the optimum number if water isoverheated each cycle. The separation efficiency is also affected bysolid loadings, pressure, and stirring strength.

The solid-to-water volume ratio affects bitumen recovery efficiency. Tomaximize energy efficiency, the solid loading should be as high aspossible. When the solid-to-water ratio is lower than 0.5:1, theextraction efficiency is not significantly affected by the volume ratio.This result indicates that the separation and floatation of bitumen inoil sands and water mixture requires liquid space. If the space is notenough for separation and bitumen floatation, bitumen could still mixedwith sand grains after compression/decompression cycles. In FIG. 2, oilsands are extracted under high temperature (from 102° C. to 105° C.) andthe extraction efficiency decreases with higher solid loading. To keepconstant volume ratio in the experiments, water is added into theextraction vessel to compensate the water evaporated duringcompression/decompression cycles.

3.

Processing time of each cycle can depend on the gas compressor capacityand heating capability of the device. Normally, 4 to 6 cycles take about4 to about 8 minutes when gas is compressed into the separation vesselby a gas compressor. When nitrogen or CO₂ is injected in the extractionvessel from a gas cylinder, each compression/decompression cycle takesless than 40 seconds when the extraction temperature is lower than thenormal pressure boiling point of water. In each cycle the water can beoverheated because each time decompression procedure decreases watertemperature. As such, it can take a little longer time to heat up wateroils sands mixture over water's normal pressure boiling point for nextcompression cycle.

4.

The bitumen content in Utah oil sands sampled from Asphalt Ridge wasmeasured by Soxhlet extraction method. Briefly, the oil sands areextracted with hexane and toluene for 48 hours (2×24 hour). Mass balancecalculation shows that Asphalt Ridge oil sands contain about 12±1.7%bitumen. It has been reported that Utah oil sands contain less fines(e.g., 7-8% by weight) than Canadian oil sands (>15% by weight), and thebitumen recovered has ultra high viscosity. Compared to 5 Pa·s ofCanadian Athabasca oil sands bitumen at 50° C., viscosity of AsphaltRidge oil sands bitumen is about 80 Pa·s at 50° C. The viscositydifference indicates that HWEP is not efficient for Utah oil sands. Itwas found that Asphalt Ridge bitumen on average contains about 48.47% C,11.0% H, 1.06% N, 0.44 S, and 3.03% O. The inorganic solids in Utah oilsands are quartz, plagioclase, microcline, chlorite, calcite, dolomite,and mica.

5.

The recovery of bitumen from oil sands with overheated water wasstudied. When water is overheated and under higher pressure, suchas >100 psi, the temperature has higher extraction efficiency (FIGS. 3,4, and 5). Also more intensive stirring can separate a little morebitumen. FIGS. 3, 4 and 5 also show that pressurized hot waterextraction also works when water temperature is lower than the normalpressure boiling point; however, the separation and recovery rate islower. The bitumen recovered by overheated water separation processcontains moisture and 5±2% by weight of solid (dry weight). The solid inbitumen can be separated by filtration of toluene-diluted bitumen.

6.

The pressure cycle process using air as the gas was tested under thenormal pressure boiling point of water (e.g., 100° C.). In this process,all the procedures and conditions are the same as those of theoverheated water process described above. The only difference is thatthe mixture was not heated higher than the normal pressure boiling pointof water after the vessel was pressurized. FIGS. 3, 4, and 5 show thatthe recovery efficiency of bitumen is sensitive to temperature, andthere is a turning point at which efficiency is decreased. When thetemperature is lower than 80° C., the separation rate of bitumen fromoil sands is slower. The temperature of water in FIGS. 3, 4, and 5 isthe average temperature.

The extraction efficiency curves in FIG. 3 and FIG. 4 show that when thetemperature is lower than 75° C., bitumen extraction efficiency is verylow. This could be caused by high viscosity of bitumen under 75° C. Allthe curves <100 degree in FIGS. 3, 4, and 5 show that after the initialfive cycles the bitumen separation amount is proportional to thecompression/decompression cycle numbers. This indicates that bitumencould have two different dispersing situations in oil sands: looselyattached and tightly attached. The separation amount of tightly attachedbitumen could be proportional to the amount of air dissolved in water.When the pressure is higher than 100 psi and temperature is higher than75° C., more than 80% bitumen can be extracted after 20 to 25 cycles.

If the temperature is lower than the normal pressure boiling point ofwater, the recovery efficiency is greatly affected by the pressure. Thiscould be due to the low solubility of air in water at high temperature.Also, since water is a liquid at less than about 100° C. at 1 atm, theworking media in the process is dissolved air in an aqueous phaseinstead of being a vapor generated by overheated water. The separationcapacity of each decompression step can be determined by the amount ofdissolve air in the water. Higher pressures dissolve more air into theaqueous phase. Additionally, FIGS. 3, 4, and 5 show that after aninitial set of cycles (e.g., 3-4 cycles), the recovery of bitumen tocycle number is almost linear. This may indicate that after some looselyattached bitumen is separated, the remaining bitumen is mostly libratedfrom the oil sands surface by microbubbles. Different from HWEP, therecovery efficiency of bitumen under overheated condition using pressurecycles is not greatly affected by the pressure. Accordingly, thepressure cycle process using overheated water may have an increasedagitation effect due to releasing of potential heat. As shown, less than5 cycles can recover 90% bitumen.

When the oil sands extraction vessel is pressurized at elevatedpressure, the water and oil sands mixture could be heated over 100degree (° C.). The above-boiling temperature is from 102° C. to 105° C.The volume ratio of oil sands to water is controlled at 0.5:1. The bulkdensity of oil sands is about 2.1 g/cm³. Minimal water use is desirable.However, when the volume ratio is lower than 0.5:1, high oil sandsloading can result in lower bitumen recovery efficiency since themixture doesn't have enough space for bitumen floatation.

7.

The use of CO₂ in the pressure cycle process was studied. The operationconditions of CO₂ assisted extraction of bitumen from oil sands was thesame as the process described above. The only difference is that CO₂ wasinjected into the hot water instead of air or other gas. FIG. 6 showsthat CO₂ assisted pressurized extraction of bitumen works at temperaturethat is much lower than the lowest temperature of air pressurized hotwater extraction process. The ability to perform the extraction at alower temperature with CO₂ may be due to the relative high solubility ofCO₂ in bitumen compared air. After CO₂ is injected into oil sand slurry,the decompression can generate gas bubbles in the aqueous phase and alsogenerate gas bubbles in bitumen. This can accelerate separation andfloatation of bitumen. It has been shown that the bitumen recovered fromoil sands at 85° C. contains about 12±3% by weight of sand, but thebitumen recovered from oil sands at 55° C. contains about 30±3% byweight of sand. This difference shows that although decompression canliberate and float bitumen, the higher viscosity of bitumen at the lowtemperature, such as 55° C., can cause the separation of bitumen andsand grains to be less complete.

Since the separation rate and floatation rate of bitumen from oil sandsis determined by the amount of gas dissolved in air, pressurizing highersoluble gas into the extraction mixture could have higher extractionrate. When carbon dioxide (CO₂) is pressurized into the separationvessel instead of air, higher extraction rate is observed. Results showthat CO₂ extraction is more effective and faster compared to extractionby air. At higher temperature (85° C.) more than 90% by weight ofbitumen can be extracted after 20 cycles. Even at low temperature whereextraction by air is not effective, more than 80% bitumen is extracted.This can be due to increased compatibility of CO₂ with bitumen (orhigher solubility of CO₂ in bitumen). During decompression, expansion ofCO₂ bubbles in bitumen makes separation (prying bitumen from sands) andfloatation of bitumen much faster.

8.

A general hot water separation process was conducted to evaluatecompression/decompression effects. In a beaker filled with boilingwater, oil sands were added into the aqueous phase and stirred underheat. The bitumen brought to the surface was collected while stirring.It was found that it takes at least 3 hours to recover the bitumen fromthe oil sands. This indicates that the compression/decompression cyclesof the pressure cycle process is more effective than without pressurecycles, and the separation of bitumen from oil sands takes longerwithout pressure cycles.

9.

The pH influence on separation efficiency is also evaluated. When pH isnot controlled during bitumen extraction, pH of the tailings water canbe about 8 after processing. In order to study influence of pH onrecovery efficiency, caustic reagent solution (4 M NaOH) was added inthe extraction system. Separation efficiencies of three levels of pH(pH=9-10, 10-11, and 11-15) were tested. For 1:1 solid loading (volumeratio) and 5 cycles under overheated condition, the amounts of separatedbitumen are compared under different pH conditions.

FIG. 7 shows that adding NaOH is not beneficial for the pressure cycleprocess. When pH is higher than 11, the bitumen is emulsified in theaqueous phase. Although air floatation can increase the recovery ofbitumen, the bitumen emulsified in water is still more than 20 wt %.Accordingly, more chemicals and additional procedures would be needed torecover bitumen. Therefore, caustic reagents are not needed for thepressure cycle process of the present invention. It was observed thatwhen no caustic reagent is used in the process, the solid and fines canprecipitate in several minutes, and the separation of solid from hotwater and bitumen froth is very simple. This allows for the quickrecycling of hot water, which can dramatically decrease the amount ofwater and save more energy.

The bitumen extraction efficiency is greatly affected by pH. Inexperiments in which NaOH solution was added into hot water, theextraction efficiency decreased at pH higher than 9.5 (FIG. 7). At pH11.5, less than 40% bitumen could be collected in the extraction vessel.Theoretically, adding caustic reagents such as NaOH and Na₂CO₃ canenhance bitumen separation from sand grains, but emulsification ofbitumen in water could decrease extraction efficiency (not shown). Alsoprecipitation rate of sand grains and fines at higher pH is very slow(now shown). Since the compression/decompression process explores gasbubble separation effects to separate bitumen from oil sand grains andthe separation efficiency is relatively high, caustic reagents are notnecessary for extraction. It is possible to increase bitumen extractionefficiency and enhance bitumen quality using caustic reagents when theextraction temperature is low than 80° C. However, addition of causticreagents may impose quality concerns on water and sand, and may need tobe treated.

When no caustic agent is used, the hot water can be directly recycledfor next batch of extraction because precipitation of the sand and finein hot water is fast following extraction. Also the organicconcentration in the water is very low since no chemical additives(e.g., surfactant and caustics) are added to the process.

10.

Canadian high-grade oil sands containing 12.4±3.3% by weight bitumen andCanadian low-grade oil sands containing 6.4±1.2% bitumen are processedby the hot water extraction method assisted by pressure cycles. When CO₂is injected into the Canadian high-grade oil sands and hot watermixture, even at low temperature more than 80% by weight bitumen isextracted (FIG. 8A). However, bitumen extracted at relative lowtemperature (65° C. and 55° C.) contains more sand grains. This meansthe floatation rate is too fast compared to the separation rate and thebitumen containing sand grains is floated before separation of bitumenfrom oil sand grains occurs sufficiently. Extraction of bitumen usingair or air/CO₂ mixture has relative low extraction rate (FIG. 8B) butthe extracted bitumen contains less sands. Pressurizing air/CO₂ mixtureinto the extraction vessel can adjust separation rate and flotationrate. Thus, it is possible to inject fuel combustion exhaust into theextraction vessel because the exhaust can contain about 20% CO₂. WhenCanadian high-grade oil sands is extracted at temperature higher thanwater's normal pressure boiling temperature, no large differences areobserved using air and CO₂ as the compression gas because the bubblesgenerated are water vapor (boiling water) and more than 90% bitumen canbe extracted.

As shown in FIG. 9, the extraction efficiency of Canadian low-grade oilsands is normally higher than 80% for 20 cycles while CO₂ extractionrate is higher than that using air. Different from how the bitumen isdispersed in the Canadian high-grade oil sands, the bitumen in Canadianlow-grade oil sands is prone to accumulate in the bitumen rich sandgrains. Therefore, tailored contact conditions may be needed to avoidfloating the bitumen rich oil sand grains without sufficient separationof bitumen from the oil sands.

11.

The bitumen quality is another important consideration. The sandconcentration in the extracted bitumen increases when extractiontemperature decreases (FIG. 10). Compression/decompression cycling hascombined bitumen separation and bitumen extraction procedures in onestep. Separation and floatation are competing processes that determinethe bitumen quality. Results show that if pure CO₂ is used as theextraction gas, the extracted bitumen contains a higher sand content.The sand concentration in extracted bitumen is also affected by how thebitumen is dispersed in oil sands. For Canadian high-grade bitumen, CO₂extraction can obtain bitumen with >70% sand. This means that bitumenand sand mixture might be well mixed together and be floated beforeseparation occurs. If air and CO₂ mixture (2:1) is pressurized into toextraction vessel instead of using air or CO₂ alone, extracted bitumencan contain <30% sand and the extraction rate is still high. Resultsshow that the extraction rate and the bitumen quality are also affectedby the stirring intensity. Higher agitation intensity shows relativelyhigher extraction rate and higher bitumen quality. So for different oilsand, the extraction parameters, including temperature, pressure, numberpressure cycles, gas composition, solid/water ratio, and stirringintensity can be optimized to minimize the cost and increase the yield.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope. All references recitedherein are incorporated herein in their entirety by specific reference.

The present disclosure is not to be limited in terms of the particularembodiments described in this application, which are intended asillustrations of various aspects. Many modifications and variations canbe made without departing from its spirit and scope, as will be apparentto those skilled in the art. Functionally equivalent methods andapparatuses within the scope of the disclosure, in addition to thoseenumerated herein, will be apparent to those skilled in the art from theforegoing descriptions. Such modifications and variations are intendedto fall within the scope of the appended claims. The present disclosureis to be limited only by the terms of the appended claims, along withthe full scope of equivalents to which such claims are entitled. It isto be understood that this disclosure is not limited to particularmethods, reagents, compounds compositions or biological systems, whichcan, of course, vary. It is also to be understood that the terminologyused herein is for the purpose of describing particular embodimentsonly, and is not intended to be limiting.

With respect to the use of substantially any plural and/or singularterms herein, those having skill in the art can translate from theplural to the singular and/or from the singular to the plural as isappropriate to the context and/or application. The varioussingular/plural permutations may be expressly set forth herein for sakeof clarity.

It will be understood by those within the art that, in general, termsused herein, and especially in the appended claims (e.g., bodies of theappended claims) are generally intended as “open” terms (e.g., the term“including” should be interpreted as “including but not limited to,” theterm “having” should be interpreted as “having at least,” the term“includes” should be interpreted as “includes but is not limited to,”etc.). It will be further understood by those within the art that if aspecific number of an introduced claim recitation is intended, such anintent will be explicitly recited in the claim, and in the absence ofsuch recitation no such intent is present. For example, as an aid tounderstanding, the following appended claims may contain usage of theintroductory phrases “at least one” and “one or more” to introduce claimrecitations. However, the use of such phrases should not be construed toimply that the introduction of a claim recitation by the indefinitearticles “a” or “an” limits any particular claim containing suchintroduced claim recitation to embodiments containing only one suchrecitation, even when the same claim includes the introductory phrases“one or more” or “at least one” and indefinite articles such as “a” or“an” (e.g., “a” and/or “an” should be interpreted to mean “at least one”or “one or more”); the same holds true for the use of definite articlesused to introduce claim recitations. In addition, even if a specificnumber of an introduced claim recitation is explicitly recited, thoseskilled in the art will recognize that such recitation should beinterpreted to mean at least the recited number (e.g., the barerecitation of “two recitations,” without other modifiers, means at leasttwo recitations, or two or more recitations). Furthermore, in thoseinstances where a convention analogous to “at least one of A, B, and C,etc.” is used, in general such a construction is intended in the senseone having skill in the art would understand the convention (e.g., “asystem having at least one of A, B, and C” would include but not belimited to systems that have A alone, B alone, C alone, A and Btogether, A and C together, B and C together, and/or A, B, and Ctogether, etc.). In those instances where a convention analogous to “atleast one of A, B, or C, etc.” is used, in general such a constructionis intended in the sense one having skill in the art would understandthe convention (e.g., “a system having at least one of A, B, or C” wouldinclude but not be limited to systems that have A alone, B alone, Calone, A and B together, A and C together, B and C together, and/or A,B, and C together, etc.). It will be further understood by those withinthe art that virtually any disjunctive word and/or phrase presenting twoor more alternative terms, whether in the description, claims, ordrawings, should be understood to contemplate the possibilities ofincluding one of the terms, either of the terms, or both terms. Forexample, the phrase “A or B” will be understood to include thepossibilities of “A” or “B” or “A and B.

In addition, where features or aspects of the disclosure are describedin terms of Markush groups, those skilled in the art will recognize thatthe disclosure is also thereby described in terms of any individualmember or subgroup of members of the Markush group.

As will be understood by one skilled in the art, for any and allpurposes, such as in terms of providing a written description, allranges disclosed herein also encompass any and all possible subrangesand combinations of subranges thereof. Any listed range can be easilyrecognized as sufficiently describing and enabling the same range beingbroken down into at least equal halves, thirds, quarters, fifths,tenths, etc. As a non-limiting example, each range discussed herein canbe readily broken down into a lower third, middle third and upper third,etc. As will also be understood by one skilled in the art all languagesuch as “up to,” “at least,” “greater than,” “less than,” and the likeinclude the number recited and refer to ranges which can be subsequentlybroken down into subranges as discussed above. Finally, as will beunderstood by one skilled in the art, a range includes each individualmember. Thus, for example, a group having 1-3 cells refers to groupshaving 1, 2, or 3 cells. Similarly, a group having 1-5 cells refers togroups having 1, 2, 3, 4, or 5 cells, and so forth.”

While various aspects and embodiments have been disclosed herein, otheraspects and embodiments will be apparent to those skilled in the art.The various aspects and embodiments disclosed herein are for purposes ofillustration and are not intended to be limiting, with the true scopeand spirit being indicated by the following claims.

1. A method for extracting hydrocarbons from sands, the methodcomprising: providing sands containing a hydrocarbon; mixing thehydrocarbon sands with water; heating the water before, during, or afterbeing mixed with the hydrocarbon sands; increasing the pressure within aclosed vessel containing the heated hydrocarbon and water mixture in thepresence of gas or by injecting with gas; releasing the pressure of theheated hydrocarbon and water mixture in the vessel so as to createmicrobubbles from the dissolved gas in the water mixture; and collectingthe hydrocarbon from the water.
 2. A method as in claim 1, wherein thehydrocarbon is a bitumen.
 3. A method as in claim 1, wherein thehydrocarbon is a tar.
 4. A method as in claim 1, wherein the hydrocarbonincludes molecules that can be processed into fuel.
 5. A method as inclaim 1, wherein the gas is selected from the group consisting of air,N₂, O₂, CO₂, Ar, BF₃, CH₄, C₂H₂, C₂H₄, H₂S, C₂C₆, C₃H₆, C₃H₈, 1-butene,1,3-butadiene, vinyl chloride, 1,1,1,2-tetrafluoroethane, isobutane,n-butane, isobutene, or any mixtures thereof.
 6. A method as in claim 1,wherein the gas includes carbon dioxide.
 7. A method as in claim 1,wherein the sands and water are conditioned in batch tumblers orconditioning drums or are mixed during transport through a pipeline. 8.A method as in claim 1, wherein the process is performed with at leastone of the following: increasing the pressure to a range of about 10 toabout 210 psi followed by reducing the pressure by at least 10 psi;maintaining the temperature between about 20 degrees C. to about 120degrees C.; cycling the pressure for about 2 to about 30 pressurecycles; solid water volume ratio is from 0.1:1 to 2:1; increasing thepressure at a rate of compression that is about 5 to about 300 secondsto reach maximum pressure; or decreasing the pressure at a rate ofdecompression that is about 0.01 to about 300 seconds to vent to reachambient pressure or any other lowered pressure.
 9. A method as in claim1, further comprising introducing the hydrocarbon and water into primaryseparation vessel (PSV).
 10. A method as in claim 9, further comprisingsettling the mixture into stratified layers in the PSV: impure bitumenfroth on the top; a combination of bitumen, sand, clay and water in themiddle (middlings); and sand precipitated to the bottom.
 11. A method asin claim 10, further comprising pumping the precipitated sand into asettling basin with water to form tailings.
 12. A method as in claim 11,further comprising separating the hydrocarbon from the tailings.
 13. Amethod as in claim 10, further comprising further separating andcleaning the middlings by gas injection and steam de-aeration.
 14. Amethod as in claim 13, further comprising recovering the hydrocarbonfrom the middlings.
 15. A method as in claim 10, further comprisingrecovering the hydrocarbon from the froth.
 16. A method as in claim 1,wherein the process is substantially devoid of adding caustic agents tothe hydrocarbon and water mixture.
 17. A method for extractinghydrocarbons from particle, the method comprising: providing a particlecontaining a hydrocarbon; mixing the hydrocarbon-containing particlesands with water; heating the water before, during, or after being mixedwith the hydrocarbon-containing particle; increasing the pressure of theheated mixture within a closed vessel; releasing the pressure in thevessel so as to create microbubbles in the mixture that liberate thehydrocarbon from the particle; and collecting the hydrocarbon from thewater and particle.
 18. A method as in claim 17, wherein the pressure isincreased by decreasing the volume of the vessel.
 19. A method as inclaim 17, wherein the pressure is increased by increasing the number ofmolecules in the vessel.
 20. A method as in claim 17, wherein thepressure is increased by increasing the temperature in the vessel.
 21. Amethod as in claim 17, wherein the pressure is increased by injecting agas into the vessel.
 22. A method as in claim 21, wherein the gas isselected from the group consisting of air, N₂, O₂, CO₂, Ar, BF₃, CH₄, C₂11 ₂, C₂H₄, H₂S, C₃H₆, C₃H₈, 1-butene, 1,3-butadiene, vinyl chloride,1,1,1,2-tetrafluoroethane, isobutane, n-butane, isobutene, or anymixtures thereof
 23. A method as in claim 21, wherein the gas includesCO₂.
 24. A method as in claim 17, wherein the process is performed withat least one of the following: increasing the pressure to a range ofabout 10 to about 210 psi followed by reducing the pressure by at least10 psi; maintaining the temperature between about 20 degrees C. to about120 degrees C.; cycling the pressure for about 2 to about 30 pressurecycles; a solid/water volume ratio that is from 0.1:1 to 2:1; increasingthe pressure at a rate of compression that is about 5 to about 300seconds to reach maximum pressure; or decreasing the pressure at a rateof decompression that is about 0.01 to about 300 seconds to vent toreach ambient pressure or any other lowered pressure.
 25. A method as inclaim 10, further comprising introducing additional hot water toseparate the bitumen froth layer and solids.
 26. A method for extractinghydrocarbons from oil sands, the method comprising: introducing waterinto a low-pressure vessel at about 20 to about 40% of vessel capacity;heating the water to over 50 degrees C. and less than 120 degrees C.;introducing oil sands into the vessel at a solid/water volume ratio ofabout 0.1 to about 3 volume to form a water/oil sands mixture; closingand pressuring the vessel with a gas to a pressure of about 25 to about210 psi; maintaining the temperature of the water/oil sands mixturebetween about 20 degrees C. to about 120 degrees C.; decompressing thepressure in the vessel so as to generate gaseous microbubbles thatrelease the hydrocarbon from the oil sands; and recovering thehydrocarbon from the water and sands.
 27. A method as in claim 26,wherein the process is performed with at least one of the following:increasing the pressure to a range of about 10 to about 150 psi followedby reducing the pressure by at least 10 psi; maintaining the temperaturebetween about 50 degrees C. to about 110 degrees C.; cycling thepressure for about 2 to about 30 pressure cycles; a solid/water volumeratio that is from 0.1:1 to 2:1; increasing the pressure at a rate ofcompression that is about 5 to about 300 seconds to reach maximumpressure; or decreasing the pressure at a rate of decompression that isabout 0.01 to about 300 seconds to vent to reach ambient pressure or anyother lowered pressure.
 28. A method as in claim 27, wherein thetemperature is obtained by injecting steam or a heating jacket.
 29. Amethod as in claim 28, wherein the heated water and oil sands are mixedin a fluidic passageway and pumped into the vessel.
 30. A method forextracting hydrocarbons from sands, the method comprising: providingsands containing a hydrocarbon; mixing the sand containing thehydrocarbon with water; cycling the pressure of the mixture in a vesselby increasing the pressure and then decreasing the pressure so as tochange gas solubility in the water and form gaseous microbubbles in themixture; and collecting the hydrocarbon from the water and sands.
 31. Amethod as in claim 30, further comprising introducing a gas into thevessel, wherein the gas is selected from the group consisting of includeammonia, ozone, chlorine, air, nitrogen, oxygen, carbon monoxide, carbondioxide, argon, helium, water vapor, BF₃, CH₄, C₂H₂, C₂ 14 ₄, H₂S, C₂H₆,C₃H₆, propane, 1-butene, 1,3-butadiene, vinyl chloride,1,1,1,2-tetrafluoroethane, isobutane, n-butane, and sobutene andcombinations thereof.
 32. A method as in claim 30, wherein the processis performed with at least one of the following: increasing the pressureto a range of about 10 to about 150 psi followed by reducing thepressure by at least 10 psi; maintaining the temperature between about50 degrees C. to about 110 degrees C.; cycling the pressure for about 2to about 30 pressure cycles; a solid/water volume ratio that is from0.1:1 to 2:1; increasing the pressure at a rate of compression that isabout 5 to about 300 seconds to reach maximum pressure; or decreasingthe pressure at a rate of decompression that is about 0.01 to about 300seconds to vent to reach ambient pressure or any other lowered pressure.